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RX-7 2nd Gen Specific (1986-92) RX-7 1986-92 Discussion including performance modifications and technical support sections.

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Old 05-05-2012, 12:34 PM   #16
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Originally Posted by Sharingan 19 View Post
Your lean afrs during cruise are not caused by the stock FPR or its lack of adjustment. The Wlabro 255 will outflow the stock FPR and if anything will cause a rich condition, not lean. Raising your static fuel pressure might mask the problem but that's no the same as finding the real source.
Lean isn't the issue it is the 2 to 3 lamba bounce I get at cruise that I worry about and I am trying to fix.






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Old 05-05-2012, 02:09 PM   #17
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bouncing between what and what? (in afr please, when did we start talking about lambda?)
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Old 05-05-2012, 02:22 PM   #18
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bounce from 12.0 to 16.0
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Old 05-05-2012, 03:10 PM   #19
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I had the issue of hesition and wild AFR fluxs when the car is in the closed loop mode. I have a RTEK 2.1 walbro 255 and larger secondry fuel injectors. From what I have read increasing the fuel pressure or just upgrading to FPR to one that can handle the increased flow of the fuel pump will fix the issue. I do plan on getting a fuel pressure gauge with this setup.
There's your problem

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Originally Posted by Sharingan 19 View Post
Your lean afrs during cruise are not caused by the stock FPR or its lack of adjustment. The Wlabro 255 will outflow the stock FPR and if anything will cause a rich condition, not lean. Raising your static fuel pressure might mask the problem but that's no the same as finding the real source.
Except that walbro's, whinboros', walsucks, wilpuke, all those pumps are HORRIBLE pieces of crap. I wouldn't trust one on an n/a car. Garbage

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Lean isn't the issue it is the 2 to 3 lamba bounce I get at cruise that I worry about and I am trying to fix.
You don't understand Lambda, do you?

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bouncing between what and what? (in afr please, when did we start talking about lambda?)
We can't be, mathematically a 2-3 lambda bouce would be 29-43:1

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Originally Posted by Raksj04 View Post
bounce from 12.0 to 16.0
That's AFR's, not Lambda. Lambda = actual AFR/14.7
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Old 05-05-2012, 03:19 PM   #20
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I mixed the two up it is my mistake. I meant AFR.
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Old 05-05-2012, 03:20 PM   #21
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So what is the answer then? what type of fuel pump should I use?
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Old 05-05-2012, 04:29 PM   #22
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Indeed TTT, do tell... Is your disdain for Walbro pumps your way of saying this sounds like pump failure or more along the lines of an endorsement for some uber expensive alternative that you prefer?

Rick, did you ever figure out what injectors you're running? Having the wrong presets selected probably wouldn't make for the best running conditions.

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Old 05-05-2012, 04:46 PM   #23
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afr swings at cruise are most likely attributed to the ecu falling in and out of closed loop... or not even reaching closed loop... and that could be to a variety of reasons.

Almost none of those reasons would have to do with fuel pressure. Are you running a stock 1-wire O2 for the stock ecu? If not, are you using the simulated 0-1 volt out on your wideband to the O2 input on the ecu? Have you made any adjustments to the cruise area of the map where it is now too lean and causing hesitation? If your ecu even reaching closed loop mode?

I don't think you are looking in the right place to fix your problem. These ecus were designed to work in a stock capacity with stock components... Its very easy to make a change that the ecu cannot compensate for, or even knows about. Yes these are old ecus with old technology, but the technology worked for many years before people started modifying them.
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Old 05-05-2012, 04:47 PM   #24
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I beileve that they are 720's if I change the computer to anything else it is scary.

when I 1st posted this I was directed to another thread on the evil fourm that stated a few people had the same issue and their fix was to replace the FPR and turn up the pressure a little. I also read in street rotary that running a high fuel pressure could help to atomize the fuel better.
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Old 05-05-2012, 04:51 PM   #25
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afr swings at cruise are most likely attributed to the ecu falling in and out of closed loop... or not even reaching closed loop... and that could be to a variety of reasons.

Almost none of those reasons would have to do with fuel pressure. Are you running a stock 1-wire O2 for the stock ecu? If not, are you using the simulated 0-1 volt out on your wideband to the O2 input on the ecu? Have you made any adjustments to the cruise area of the map where it is now too lean and causing hesitation? If your ecu even reaching closed loop mode?

I don't think you are looking in the right place to fix your problem. These ecus were designed to work in a stock capacity with stock components... Its very easy to make a change that the ecu cannot compensate for, or even knows about. Yes these are old ecus with old technology, but the technology worked for many years before people started modifying them.
it is a narrow output from the wideband. I haven't driven the car with the pda hooked up in a while. However the AFR will bounce inbetween 2,500 to 3,500 Rpm with low vaccum. When I get on in even into boost the AFR will stay pretty steady.
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Old 05-05-2012, 05:53 PM   #26
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Quote:
Originally Posted by FerociousP View Post
afr swings at cruise are most likely attributed to the ecu falling in and out of closed loop... or not even reaching closed loop... and that could be to a variety of reasons.

Almost none of those reasons would have to do with fuel pressure. Are you running a stock 1-wire O2 for the stock ecu? If not, are you using the simulated 0-1 volt out on your wideband to the O2 input on the ecu? Have you made any adjustments to the cruise area of the map where it is now too lean and causing hesitation? If your ecu even reaching closed loop mode?

I don't think you are looking in the right place to fix your problem. These ecus were designed to work in a stock capacity with stock components... Its very easy to make a change that the ecu cannot compensate for, or even knows about. Yes these are old ecus with old technology, but the technology worked for many years before people started modifying them.
Whoops... forgot to mention what I thought the original issue was.... I'm voting TPS.

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Indeed TTT, do tell... Is your disdain for Walbro pumps your way of saying this sounds like pump failure or more along the lines of an endorsement for some uber expensive alternative that you prefer?
If it's not pump failure it will be soon

My ubber expensive hella reliable badass pump that I use in my own car is a stock supra TT pump
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Old 05-05-2012, 06:33 PM   #27
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Quote:
Originally Posted by FerociousP View Post
afr swings at cruise are most likely attributed to the ecu falling in and out of closed loop... or not even reaching closed loop... and that could be to a variety of reasons.
I've driven this car and there doesn't even seem to be anything wrong. Honestly, there were no complaints about how it drove before he installed the wideband, but now that there are numbers that change, there must be an issue. My honest opinion is that this is more a case of observation bais than anything else. But what is being observed is most likely what you're referring to. In cruise I see 14.5-16 afr and under light to moderate acceleration it dips down to 12's and 13's....nothing special there.


Quote:
I don't think you are looking in the right place to fix your problem. These ecus were designed to work in a stock capacity with stock components... Its very easy to make a change that the ecu cannot compensate for, or even knows about. Yes these are old ecus with old technology, but the technology worked for many years before people started modifying them.
The Rtek 2.1 has the capacity to adjust fuel and timing so its certainly more flexible than the stock ecu....for example the ability to datalog. Rick take some logs and post them and point out exactly where the problem is occuring. Doing so will allow you/us to see what the TPS value, inj duty cycle, afr and other parameters are and allow us to do more than guess at what the problem is.

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Whoops... forgot to mention what I thought the original issue was.... I'm voting TPS.
quite possibly

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My ubber expensive hella reliable badass pump that I use in my own car is a stock supra TT pump
Hard to beat OEM for reliability. I got rid of my walbro (came installed on the car when I got it) and installed an FD pump because 1) it was loud as hell and 2) it caused the car (otherwise completely stock) to run rich, smoke on start up and occasionally not want to hot start.
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Old 05-05-2012, 08:49 PM   #28
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The car also has issues idling after 1st start up it will be fine after a few mintues of driving but it will sometimes drop really low when I put the clutch in for a stop. It will die in the 1st 5 mins of driving.
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Old 05-05-2012, 08:51 PM   #29
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Also my logs will only be with narrow band inputs I haven't wired it up for datalogging yet
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Old 05-06-2012, 09:24 PM   #30
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I have some logs but I am not sure how to share them.
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